Raw Therapee Review

A Review of Raw Therapee 4.05.2

If you are a photographer who processes digital camera raw files, then this post is for you! Some of the most exciting developments in raw processing software are taking place in open-source (as in free) software. My two favorite raw processing programs are both free to the public, and are developed by independent programmers in their spare time. The one that holds the most promise at the moment is Raw Therapee. I am currently using version 4.0 of Raw Therapee at the moment. I believe that it provides the best image quality at pixel level of any raw processing software I’ve used to date. This is largely due to two stand out features.

The first is a demosaicing algorithm named AMaZE that is a selectable option in the Preferences Menu in Raw Therapee (as of version 4.0 it is the default demosaicing setting). On low ISO (noise free) images that are well exposed, it renders the cleanest, aberration free images I can get from my raw files. Not only does it extract an excellent level of detail, it also renders shadow detail very naturally. That quality is better seen than explained. It is only when you convert a raw file that you are familiar with that you will understand what I mean. The shadows just look very natural. The other strength of AMaZE is the way it extracts every last bit of highlight detail from the raw file. That ability enhances the perceived dynamic range of the converted images.

AMaZE demosaicing does an excellent job with noise-free low ISO images. However, it is not the best choice for rendering high ISO images that tend to be noisy. You may find one of the other demosaicing options available in Raw Therapee (I use HPHD for high ISO images) better suited for high ISO images. It’s quite easy to experiment with the options available in Raw Therapee to get the best possible results.

The second feature of Raw Therapee that I consider a standout is the RL Deconvolution sharpening tool. This sharpening method, in theory, un-blurs slight motion blur and optical distortion to create a sharper image. It does not create halos like unsharp mask, and adds a pleasing, natural sharpness to images when used moderately.

While Raw Therapee does not give you the ability to edit the hue, saturation and luminance of individual colors in the way that Adobe Lightroom and other commercial raw editing programs can, on most images I find that Raw Therapee delivers the most pleasing quality. That is high praise for a free program! However, getting the best results from your images does come with a learning curve. You must read the manual to understand all the features of this software. You will not regret doing so. This is a remarkably effective tool for extracting the best possible quality form your raw files.

I find that on my 32 bit Windows Vista computer there is an occasional instability if I have Raw Therapee running with too many other programs. However, I do find this to be the most stable and speedy version of Raw Therapee yet. My compliments to the developers for putting together such an ambitious and effective product for the open source market.